a. Field of the Invention
The present invention relates generally to adjustable fittings for use with straps and cords, and, more particularly, to an adjustable link that functions cooperatively with an elastomeric strap having a flattened cross-section.
b. Related Art
Links of various kinds (e.g., buckles, couplings and other forms of fittings) have long been used with various kinds of straps. Some of the simplest are basic belt buckles and double-D rings; other examples include clasp-type fittings, in which a pivoting part engages the strap (e.g., suspender buckles), and buckles/strap adjusters that utilize sliding bar mechanisms. Examples of the latter in the prior art include the devices shown in U.S. Pat. No. 1,514,227 (Prentice); U.S. Pat. No. 2,743,427 (Davis); U.S. Pat. No. 2,938,254 (Gaylord); U.S. Pat. No. 3,975,800 (Färlind); U.S. Pat. No. 3,999,254 (McLennon); U.S. Pat. No. 4,131,976 (Bengtsson); U.S. Pat. No. 4,608,735 (Kasai); U.S. Pat. No. 4,525,901 (Kraus); U.S. Pat. No. 5,317,788 (Esposito et al.) and U.S. Pat. No. 5,331,726 (Suh). In general, the object of the devices is to hold the strap when under tension, but allow the length of the strap to be adjusted as necessary.
Although many types of adjustable links are therefore known in the art, they tend to share a number of deficiencies. To begin with, most are to a greater or lesser degree somewhat “fiddly” to operate, especially when being released in order to adjust the length of the strap. Many also employ somewhat complex mechanisms with multiple parts, which impacts not only the cost of the device but often its long term durability as well. Many are also inherently limited to metal construction, which again is relatively costly and also presents a number of other drawbacks; for example, metal tends to abrade/scratch adjoining materials and surfaces, and also is far more likely to cause injury (e.g., an eye injury) in the event that it comes loose, particularly if the strap is under a load.
In addition, prior types of adjustable links have used bars, jaws or other mechanisms or structures that dig into or bite against the strap in a manner that is ultimately harmful to the material of the latter, especially over extended use. Given the characteristics of traditional strap materials with which these devices have been used (e.g., nylon webbing), the inherent damage (e.g., fraying and crushing/kinking of fibers) was deemed acceptable since the overall strength of the strap remained largely intact, at least for a service life of adequate length. However, for newer, elastomeric-type straps, formed of rubber or similar materials, such damage is unacceptable since it is liable to lead to complete failure of the strap and potentially hazardous consequences, especially when the strap is under a heavy tension load.
Accordingly, there exists a need for an adjustable link for use with a strap, that is quick and convenient to use, and avoids the need to “fiddle” excessively with the mechanism and/or strap to release the latter for adjustment. Furthermore, there exists a need for such a link that operates without causing damage to the material of the strap, particularly modern straps formed of an elastomeric material. Still further, there exists a need for such a link that can be used with a wide range of fittings that may be employed with such straps. Still further, there exists a need for such a link that is economical to produce, light in weight, durable, and unlikely to present a hazard to personnel and/or surrounding materials/surfaces during use.